Generally described, computing devices utilize a communication network, or a series of communication networks, to exchange data. Companies and organizations operate computer networks that interconnect a number of computing devices to support operations or provide services to third parties. The computing systems can be located in a single geographic location or located in multiple, distinct geographic locations (e.g., interconnected via private or public communication networks). Specifically, data centers or data processing centers, herein generally referred to as a “data center,” may include a number of interconnected computing systems to provide computing resources to users of the data center. The data centers may be private data centers operated on behalf of an organization or public data centers operated on behalf, or for the benefit of, the general public.
To facilitate increased utilization of data center resources, virtualization technologies may allow a single physical computing device to host one or more instances of virtual machines that appear and operate as independent computing devices to users of a data center. The single physical computing device can create, maintain, delete, or otherwise manage virtual machines in a dynamic manner. In some scenarios, various computing devices may be associated with different combinations of operating systems or operating system configurations, virtualized hardware resources and software applications to enable a computing device to provide different desired functionalities, or to provide similar functionalities more efficiently. Further, virtual machines can themselves be partitioned into multiple isolated virtual systems, called “containers.” The virtual machine controls allocation of resources such as processing power and memory, and each container has its own process and network space in which the container can, for example, execute software programs.
In turn, users can request computer resources from a data center, including single computing devices or a configuration of networked computing devices, and be provided with varying numbers of virtual machine resources. In a computing environment, a user's access to resources can be limited based presently available resources, a service level, a maximum bandwidth, etc. For example, a user may be limited to a certain number of concurrently-instantiated virtual machines. Consequently, when a request is to allocate resources to execute a software program, it is beneficial to minimize the execution time in order to make the resources available again as soon as possible. If a request to allocate more resources arrives while the maximum resources are allocated, the request may be placed in a queue and then processed (e.g., after earlier queued requests) when resources come available.